Cooling element for refrigerating systems



July 16, 1935. A. R. THOMAS COOLING ELEMENT FOR REFRIGERATING SYSTEMS Filed Dec. 2, 1932 5 Sheets-Sheet l INVENTOR. 42%: @2- Wm ATTORNEY.

July 16, 1935. R THOMAS 2,008,343

COOLING ELEMENT FOR REFRIGERATING SYSTEMS Filed Dec. 2, 1952 5 Sheets-Sheet IN VENTOR.

% ATTORNEY.

July 16, 1935. A. R. THOMAS COOLING ELEMENT FOR REFRIGERATING SYSTEMS Filed Dec. 2, 19 32 3 $h&e0s-Sheet 3 7 INVENTOR. Wad J1 Wamaa Patented July 16, 1935 UNITED STATES PATENT OFFICE COOLING ELEMENT FOR REFRIGERATING SYSTEMS Application December 2, 1932, Serial No. 645,432

10 Claims. (01. 62-99) My invention relates to refrigeration and more particularly to a new and improved cooling element for a system which produces refrigeration by the evaporation of liquid cooling fluid by dif- 5 fusion into an inert auxiliary gas.

In refrigerators, particularly of the domestic type, refrigeration is usually required both at a temperature below freezing for making ice cubes and the like and a temperature above freezing for cooling air in the storage compartment for the proper preservation of comestibles. For best thermal efficiency, such a refrigerator should have a low temperature cooling element adapted for good thermal contact with the containers of substance to be frozen, such as ice trays, and a higher temperature cooling element having extensive heat transfer surfaces for cooling the air in the storage compartment. Since the warmest air is at the top of the compartment the air cooling element should be located in the uppermost part thereof.

For use with a system which produces refrigeration by the evaporation of liquid cooling fluid into an auxiliary as there have-been proposed cooling elements or evaporators arranged for the circulation of the inert auxiliary gas therethrough in a series path and an opposite flow of liquid cooling fluid whereby one part of the cooling element is at a higher temperature than the other part due to the difference in partial pressure of the cooling fluid vapor in the respective parts. However, such evaporators or cooling elements have been of the usual type comprising a closed vessel provided with a plurality of liquid spreadin a series path, and they are not adapted for utilization of the two-temperature effect.

In accordance with my invention there is provided a cooling element of the coil type as disclosed in an application by Sven W. E. Anderson and William R. Hainsworth Serial No. 645,422, assigned to the same assignee as the present invention, having a portion defining a low temperature chamber for freezing ice cubes and the like and a portion thereabove at a higher temperature adapted for cooling the air in the storage compartment. My invention will be more completely understood by reference to the following description taken in connection with the accompanying drawings, in which, Fig. l is a side elevation of the cooling element contemplated by my invention;

Fig. 2, a front end view of the cooling element in Fig. 1;

ing baiiies which also direct the circulating gas Fig. 3, a plan view of the cooling element in Figs. 1 and 2;

Fig. 4, a detailed section taken on line 4-4 in Fi 1;

Fig. 5, a section taken on line 5-5 Fig. 1;

Fig. 6, a section taken on line 6--6 in g. 3; and

Fig. 7, an isometric view of the cooli g element.

Referring to the drawings, a tray eceptacle open at the front end and having tray supports or shelves H is formed by an integral casting of good thermal conductive material such as aluminum. Around the closed sides of the receptacle I0 is a pipe coil l2 comprising a plurality of substantially horizontal superposed U-shaped turns between which are vertical reversed turns on each side of the receptacle. As best shown in Fig. 2,. the coil l2 .has a constantly downward slant such that liquid cooling fluid introduced at the upper end of the coil will have a continuously downward path of flow therethrough.

As shown inFig. 4, the leg portions of the U- bends along the sides of the receptacle ID are lined with a wick-like material l3. When ammonia is used as the cooling liquid, such lining preferably comprises tubes of steel gauze or the like. To facilitate construction of the coil and insertion of the gauze cylinders, the coil may be fabricated of individual U-sections. After the gauze has been inserted in the leg portions the several loops are assembled by welding together at their ends as at M in Figs. 1 and 2. In order that the coil may lie flat against the receptacle ID, the latter is provided with grooves as shown in Figs. 1 and 5 to receive the projections at the joints caused by material built up in the welding process. Integrally cast spacing lugs or bosses IS on the casing ID are provided for locating the coil with respect to the receptacle where it is mechanically and thermally secured by welding or brazing. When ammonia is used as the cooling liquid, the coil I2 is preferably made of steel and strips ll of copper or equivalent material are cast as inserts in the surface of the receptacle ID, to which strips the adjacent portions of the coil may be more readily secured than to the aluminum casting.

'The upper end of the coil I2 is connected to the lower end of the closed steel tube l8 which extends rearwardly with a slightly upward slant from above the front end of the receptacle Ill. The exterior of the tube; is provided with a plurality of heat transfer fins I9 and, as shown to that in the leg portionsof the coil l2.

In operation, inert gas such as hydrogen is circulated upwardly through coil l2 and tube l8 in series from a suitable refrigerating system, connections to which are made at the lower end 2| of the coil l2 and conduit 22 from the upper end of the tube I8. Liquid cooling fluid such as ammonia is introduced into the upper end of tube 8 through conduit 23 and flows downwardly through the tube I8 and then coil I2 due to the continuously downward slant of the tube and coil described above and is distributed in finely divided form over the interior of the tube and the coil by capillarity of the steel mesh lining thereby presenting an extensive surface area which facilitates evaporation of the liquid by diffusion into the inert gas. A conduit 24 from the lower end of the coil I2 is provided for draining unevaporated liquid back to the refrigerating system.

Due to the lower partial pressure of refrigerant vapor in the coil l2 than in tube l8, evaporation in the latter occurs at a higher temperature than in the coil, wherefore freezing of the ice cubes and the like may be accomplished rapidly at a low temperature and the air in the storage compartment cooled by passage over the extensive surfaces of the tube l8 which are at a temperature above freezing. The finned tube I8 is the highest part of the cooling element and may therefore be located in the uppermost part of the storage compartment where accumulates the warmest air, cooling of which is accomplished without the usual formation of frost due to the above-freezing temperature of the cooling surface.

It will be obvious to those skilled in the art that various changes may be made in the construction and arrangement without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and. described in the specification but only as indicated in the following claims.

I claim:

1. A cooling element comprising a conduit having a slightly downward slope and provided exteriorly with extensive heat transfer surfaces, a pipe coil adapted for passage of inert gas and continuously downward flow of liquid therethrough, means within said coil and conduit for retaining liquid in a manner to present extensive surface area of the liquid to the gas, the upper end of said coil being connected to the lower end of said conduit whereby inert gas may be circulated upwardly through said coil and conduit in series respectively, and a connection for liquid cooling fluid to the upper end of said conduit.

2. A cooling element comprising a pipe coil adapted for upward circulation of inert gas and continuously downward flow of liquid therethrough, the upper part of said coil being provided exteriorly with extensive heat transfer surfaces, a heat conducting support for objects to be cooled in thermal conductive relation with the lower part of said coil, means within said coil for retaining liquid in a. manner to present extensive surface area of the liquid to the. gas, and a connection for liquid cooling fluid to the upper end of said Cell. I

3. A cooling element comprising an open front chamber formed by a casing of heat conducting material, a pipe coil adapted for upward circulation of inert gas and continuously downward flow of liquid therethrough, the upper part of said coil being provided exteriorly with extensive heat transfer surfaces and the lower part of said coil being arranged in thermal conductive relation with the closed sides of said casing, means within said coil for retaining liquid in a manner to present extensive surface area of the liquid to the gas, and a connection for liquid cooling fluid to the upper end of said coil.

4. Acooling element comprising an open front freezing compartment formed by a casing of cast aluminum, a. steel conduit adapted for upward circulation of gas and continuously downward flow of liquid therethrough, a plurality of heat transfer fins on the upper part of said conduit, the lower part of said conduit having superposed U-shaped turns around the closed sides of said casting, copper inserts in the surface of said casting to which are welded portions of said turns, lining of steel mesh in said conduit for retaining liquid in finely divided form over an extensive surface, and a connection for liquid cooling fluid to the upper end of said conduit.

5. A cooling element comprising an aluminum casting forming a plurality of superposed freezing chambers open at the front end, a steel pipe coil adapted for upward circulation of gas and continuously downward flow of liquid. therethrough, said coil having a plurality of superposed U-shaped turns around the closed sides of. said casting, a plurality of copper strip inserts in the outer surface of said casting to which are welded the leg portions of said turns, a closed steel tube above said casting extending rearwardly with a slightly upward slant from thefront end thereof, a plurality of heat transfer fins on said tube, the lower end of said tube being connected to the upper end of said coil, connections for the circulation of an inert gas upwardly through said coil and tube in series respectively,

steel mesh lining in the leg portions of said coll turns and said tube, and a connection for liquid cooling fluid to the upper end of said tube.

6. A cooling element comprising a. casing of thermal conductive material forming an open front freezing compartment, a. pipe coil adapted for upward circulation of gas and a continuously downward flow of liquid therethrough, the lower part of said coil being arranged in thermal conductive relation with closed sides of said casing, a plurality of thermal transfer fins on the upper part of said coil, and a connection for liquid cooling fluid to the upper end of said coil.

7. A cooling element comprising an aluminum casting forming an open front freezing compartment, a steel pipe coil adapted for upward circulation of gas and continuously downward flow of liquid therethrough, said coil having a plurality of superposed U-shaped turns arranged in thermal conductive relation with the closed sides of said casting, a closed steel tube above said casting extending rearwardly with a slight upward slope from the front end thereof, a plurality of heat transfer fins on said tube, the lower end of said tube being connected to the upper end of said coil, connections for the circulation of an inert gas upwardly thru said coil and tube in series respectively, means within said coil and tube for retaining liquid in a manner to present extensive surface area of the liquid to the gas, and a connection for liquid cooling fluid to the upper end of said tube.

8. A cooling element comprising a pipe coil adapted for upward circulation of inert gas and continuously downward flow of liquid therethrough, the upper part of said coil being provided exteriorly with extensive heat transfer surfaces, a thermal conductive support for objects to be cooled in thermal conductive relation with the lower part of said coil, and a connection for liquid cooling fluid to the upper end of said'coil.

9. A cooling element for a refrigeration system of the type in which liquid cooling fluid is evaporated into an auxiliary inert gas including a'pipe coil, the upper part of said coil being provided exteriorly with extensive heat transfer surfaces for cooling of air, a thermal conductive support for objects to be cooled in thermal conductive relation with the lower part of said coil, and connections for circulation of gas through said coil and continuously downward flow of liquidtherethrough so arranged that the circulating gas comes into contact with liquid in the lower part of said coil prior' to contact with liquid in the upper part of said coil whereby the upper part of said coil is at a higher temperature than the lower part of said coil due to the greater partial pressure of the cooling fluid in the upper part of said coil.

10. A cooling element for a refrigeration system of the type in which liquid cooling fluid is evaporated into an inert auxiliary gas including upper and lower elements, said upper element being provided with extensive heat transfer surfaces for cooling of air, a thermal conductive support for objects to becooled in thermal conductive relation with said lower element, and connections for circulation of gas and continuous'ly downward flow of liquid through said elements so arranged that the circulating gas comes into contact with liquid in said lower element prior to contact with liquid in said upper element whereby said upper element is at a higher temperature than said lower element due to the upper element.

ALBERT R. moms. 2o 

